The invention generally relates to a receiver that has a digital automatic gain control.
A conventional radio frequency (RF) receiver includes various gain stages for purposes of receiving a relatively small magnitude RF signal and translating the received RF signal to an intermediate frequency (IF) signal or directly to a baseband (BB) signal in a direct-conversion receiver.
The RF signal that is received by the receiver typically varies in strength; and the receiver typically has an analog circuit called an automatic gain control (AGC) circuit for purposes of adjusting an internal gain of the receiver to accommodate the range of signal strengths. Thus, the analog AGC circuit causes the receiver to generally apply more gain to weaker signals and less gain to stronger signals. If insufficient gain is applied by the receiver, then the receiver may suffer from poor signal-to-noise (S/N) performance. If, however, the receiver applies too much gain to the received RF signal, then the circuitry of the receiver may become saturated and introduce significant non-linearities to the processed signal.